Topical application of capsaicin reduces visceral adipose fat by affecting adipokine levels in high‐fat diet‐induced obese mice

Objective:

Visceral obesity contributes to the development of obesity‐related disorders such as diabetes, hyperlipidemia, and fatty liver disease, as well as cardiovascular diseases. In this study, we determined whether topical application of capsaicin can reduce fat accumulation in visceral adipose tissues.

Methods and Results:

We first observed that topical application of 0.075% capsaicin to male mice fed a high‐fat diet significantly reduced weight gain and visceral fat. Fat cells were markedly smaller in the mesenteric and epididymal adipose tissues of mice treated with capsaicin cream. The capsaicin treatment also lowered serum levels of fasting glucose, total cholesterol, and triglycerides. Immunoblot analysis and RT‐PCR revealed increased expression of adiponectin and other adipokines including peroxisome proliferator‐activated receptor (PPAR) α, PPARγ, visfatin, and adipsin, but reduced expression of tumor necrosis factor‐α and IL‐6.

Conclusions:

These results indicate that topical application of capsaicin to obese mice limits fat accumulation in adipose tissues and may reduce inflammation and increase insulin sensitivity.     

Biglycan binds to alpha- and gamma-sarcoglycan and regulates their expression during development

The dystrophin-associated protein complex (DAPC), which links the cytoskeleton to the extracellular matrix, is essential for muscle cell survival, and is defective in a wide range of muscular dystrophies. The DAPC contains two transmembrane subcomplexes-the dystroglycans and the sarcoglycans. Although several extracellular binding partners have been identified for the dystroglycans, none have been described for the sarcoglycan subcomplex. Here we show that the small leucine-rich repeat (LRR) proteoglycan biglycan binds to alpha- and gamma-sarcoglycan as judged by ligand blot overlay and co-immunoprecipitation assays. Our studies with biglycan-decorin chimeras show that alpha- and gamma-sarcoglycan bind to distinct sites on the polypeptide core of biglycan. Both biglycan proteoglycan as well as biglycan polypeptide lacking glycosaminoglycan (GAG) side chains are components of the dystrophin glycoprotein complex isolated from adult skeletal muscle membranes. Finally, our immunohistochemical and biochemical studies with biglycan null mice show that the expression of alpha- and gamma-sarcoglycan is selectively reduced in muscle from young (P14-P21) animals, while levels in adult muscle (> or = P35) are unchanged. We conclude that biglycan is a ligand for two members of the sarcoglycan complex and regulates their expression at discrete developmental ages.     

Molecular and phenotypic characterization of potential plant growth-promoting <Emphasis Type="Italic">Pseudomonas</Emphasis> from rice and maize rhizospheres

In this study, Pseudomonas species were isolated from the rhizospheres of two plant hosts: rice (Oryza sativa cultivar Pathum Thani 1) and maize (Zea mays cultivar DK888). The genotypic diversity of isolates was determined on basis of amplified rDNA restriction analysis (ARDRA). This analysis showed that both plant varieties selected for two distinct populations of Pseudomonas. The actual biocontrol and plant promotion abilities of these strains was confirmed by bioassays on fungal (Verticillum sp., Rhizoctonia solani and Fusarium sp.) and bacterial (Ralstonia solanacearum and Bacillus subtilis) plant pathogens, as well as indole-3-acetic acid (IAA) production and carbon source utilization. There was a significant difference between isolates from rice and maize rhizosphere in terms of biological control against R.  solanacearum and B.  subtilis. Interestingly, none of the pseudomonads isolated from maize rhizosphere showed antagonistic activity against R.  solanacearum. This study indicated that the percentage of pseudomonad isolates obtained from rice rhizosphere which showed the ability to produce fluorescent pigments was almost threefold higher than pseudomonad isolates obtained from maize rhizosphere. Furthermore, the biocontrol assay results indicated that pseudomonad isolated from rice showed a higher ability to control bacterial and fungal root pathogens than pseudomonad isolates obtained from maize. This work clearly identified a number of isolates with potential for use as plant growth-promoting and biocontrol agents on rice and maize.     

Cassava as a Cheap Source of Carbon for Rhizobial Inoculant Production using an Amylase-producing Fungus and a Glycerol-producing Yeast

Summary The aim of this research was to develop methods to use low-cost carbon compounds for rhizobial inoculant production. Five raw starch materials; steamed cassava, sticky rice, fresh corn, dry corn and sorghum were tested for sugar production by an amylase-producing fungus. Streamed cassava produced the highest amount of reducing sugar after fermentation. Bradyrhizobium japonicum USDA110, Azorhizobium caulinodans IRBG23, Rhizobium phaseoli TAL1383, Sinorhizobium fredii HH103, and Mesorhizobium ciceri USDA2429 were tested on minimal medium supplemented with reducing sugar obtained from cassava fermentation. All strains, except B. japonicum USDA110, could grow in medium containing cassava sugar derived from 100 g steamed cassava per litre, and the growth rates for these strains were similar to those in medium containing 0.5 (w/v) mannitol. The sugar derived from steamed cassava was further used for production of glycerol using yeast. After 1 day of yeast fermentation, the culture containing glycerol and heat-killed yeast cells, was used to formulate media for culturing bradyrhizobia. A formulation medium, FM4, with a glycerol concentration of 0.6 g/l and yeast cells (OD₆₀₀ = 0.1) supported growth of B. japonicum USDA110 up to 3.61 × 10⁹ c.f.u./ml in 7 days. These results demonstrate that steamed cassava could be used to provide cheap and effective carbon sources for rhizobial inoculant production.     

Biases for detecting arbuscular mycorrhizal fungal mixture by terminal restriction fragment length polymorphism (T-RFLP)

Terminal restriction fragment length polymorphism (T-RFLP) analysis of amplified ribosomal RNA genes is used for profiling microbial communities and sometimes for species richness and relative abundance estimation in environmental samples. However, the T-RFLP fingerprint may be subject to biases during the procedure, influencing the detection of real community structures in the environment. To investigate possible sources of T-RFLP bias, 18S rRNA gene clones derived from two arbuscular mycorrhizal fungal sequences were combined in simple pairwise mixes to assess the effects of polymerase chain reaction cycle number, plant genomic DNA purification method and varying template ratio on the template-to-product ratio as measured by relative T-RF peak area. Varying cycle numbers indicated that amplification was still in the exponential phase at the cycle numbers lower than 18, so these small cycle numbers were used for the comparison of template-to-product quantities. Relative abundance estimated from T-RF peak ratios varied with different purification procedures, but the best results, closest to input ratios, were obtained by using phenol–chloroform purification. The presence of an excess of unpurified non-target plant genomic DNA generated a bias towards lower or overestimation of relative abundance. We conclude that a low number of amplification cycles and stringent DNA purification are necessary for accurate mixed sample analysis by T-RFLP.     

Soybean cultivars affect nodulation competition of Bradyrhizobium japonicum strains

The influence of five Thai soybean cultivars on nodulation competitiveness of four Bradyrhizobium japonicum strains was investigated. Cultures of B. japonicum strains THA5, THA6, USDA110 and SEMIA5019 were mixed with each other prior to inoculating germinated soybean seeds growing in Leonard jars with nitrogen-free nutrient solution. At harvest, nodule occupancy by each strain was determined by a fluorescent antibody technique. The term ‘general competitive ability’ was introduced to describe the average competitive nodule occupancy of a strain in paired co-inoculation with a number of strains on soybean. The nodule occupancies by an individual strain were directly correlated with the proportions of that strain in the inoculum mixtures. USDA110 showed higher nodulation competitiveness than the other strains on three of the five cultivars. The Thai strain THA6 appeared to be more competitive than USDA110 on cultivar SJ5. Thus, nodulation competitiveness of the B. japonicum strains was affected by the cultivars of soybean used. This revised version was published online in August 2006 with corrections to the Cover Date.     

Detection of Bradyrhizobium spp. and B. japonicum in Thailand by primer-based technology and direct DNA extraction

Total chromosomal DNAs from 20 Bradyrhizobium spp. strains (10 strains isolated from Vigna radiata and 10 from Arachis hypogaea) and 18 B. japonicum strains isolated from Glycine max were extracted. These DNAs served as templates for REP, ERIC and RAPD primers in PCR analyses. The patterns of the resulting PCR products were analyzed and highly specific for each strain, especially when grouped together with their antibiotic-resistance profiles. A method for extracting DNA directly from soil was developed. Recovery was approximately 30 g DNA g-1 soil and the procedure yielded DNA suitable for PCR amplification.     

Depletion of Aurora A leads to upregulation of FoxO1 to induce cell cycle arrest in hepatocellular carcinoma cells

Aurora A kinase has drawn considerable attention as a therapeutic target for cancer therapy. However, the underlying molecular and cellular mechanisms of the anticancer effects of Aurora A kinase inhibition are still not fully understood. Herein, we show that depletion of Aurora A kinase by RNA interference (RNAi) in hepatocellular carcinoma (HCC) cells upregulated FoxO1 in a p53-dependent manner, which induces cell cycle arrest. Introduction of an RNAi-resistant Aurora A kinase into Aurora A-knockdown cells resulted in downregulation of FoxO1 expression and rescued proliferation. In addition, silencing of FoxO1 in Aurora A-knockdown cells allowed the cells to exit cytostatic arrest, which, in turn, led to massive cell death. Our results suggest that FoxO1 is responsible for growth arrest at the G₂/M phase that is induced by Aurora A kinase inhibition.     

Comparative study of endophytic and endophytic diazotrophic bacterial communities across rice landraces grown in the highlands of northern Thailand

Communities of bacterial endophytes within the rice landraces cultivated in the highlands of northern Thailand were studied using fingerprinting data of 16S rRNA and nifH genes profiling by polymerase chain reaction–denaturing gradient gel electrophoresis. The bacterial communities’ richness, diversity index, evenness, and stability were varied depending on the plant tissues, stages of growth, and rice cultivars. These indices for the endophytic diazotrophic bacteria within the landrace rice Bue Wah Bo were significantly the lowest. The endophytic bacteria revealed greater diversity by cluster analysis with seven clusters compared to the endophytic diazotrophic bacteria (three clusters). Principal component analysis suggested that the endophytic bacteria showed that the community structures across the rice landraces had a higher stability than those of the endophytic diazotrophic bacteria. Uncultured bacteria were found dominantly in both bacterial communities, while higher generic varieties were observed in the endophytic diazotrophic bacterial community. These differences in bacterial communities might be influenced either by genetic variation in the rice landraces or the rice cultivation system, where the nitrogen input affects the endophytic diazotrophic bacterial community.